1. Field of the Invention
The present invention relates to a technique for obtaining a two-dimensional image from information about a tomographic image obtained based on light interference.
2. Description of the Related Art
Currently, imaging apparatuses that employ optical coherence tomography (OCT) in which multi wavelength interference is utilized are being used in more and more fields of application on the human body to obtain, for example, information about internal organs with an endoscope, and information about the retina with an ophthalmologic apparatus. An imaging apparatus that is applied to the eye is becoming an essential apparatus for specialist retina out-patient clinics as an ophthalmologic device.
Such an imaging apparatus can irradiate measurement light, which is low-coherence light, on a sample and measure the backscattered light from that sample using an interference system. Further, such an imaging apparatus is widely used in the ophthalmologic diagnosis of the retina because, when applied to an eye, a high resolution tomographic image of a subject's eye can be captured by scanning measurement light over the subject's eye.
Japanese Patent Application Laid-Open No. 2011-36431 discusses a configuration capable of acquiring a surface image of an imaging target, such as a fundus surface, to confirm the imaging range of a tomographic image.
On the other hand, there is a need to more accurately confirm the position of a cross-section on the fundus surface (i.e., imaging target).
In response thereto, a technique is known for generating a pseudo two-dimensional image, from a plurality of tomographic images, in which the fundus is viewed from the front (hereinafter referred to as a “two-dimensional image”). In this technique, pixel values of a predetermined range in the depth direction obtained by one A scan are calculated. Then, by obtaining these calculated values for all the A scans, a two-dimensional image of the retina can be obtained from only tomographic images.
However, in the above-described technique, since the two-dimensional image is obtained by calculating the pixel values of a predetermined range obtained by an A scan in the depth direction of the retina, unnecessary information, such as a noise component, that is included in the depth direction information is also calculated. Consequently, the amount of effective information about an intensity image is relatively smaller, so that the quality of the intensity image may deteriorate.